Problema no envio de email - Could not access ´CDO.Message´

public string EnviaEMail(string sMsg, string sDestinatario)
        {
         
            MailMessage newMessage = new MailMessage();
            newMessage.From = "xxxxx@xxxxx.com.br";
            newMessage.To = sDestinatario.Trim();
            
            newMessage.Subject ="Sua chave de autorização" ;

          
            newMessage.Body = sMsg;
            SmtpMail.SmtpServer ="xxx.xxxx.com.br";
                                //  String.
            if (
                (newMessage.Body != String.Empty) && 
                (newMessage.Body != null        ) && 
                (newMessage.To   != String.Empty) && 
                (newMessage.From != String.Empty)
               )
            {
                
                newMessage.BodyFormat = MailFormat.Text;

                try
                {
                    
                    SmtpMail.Send(newMessage);
                     return "OK";
                } 

               
                catch (Exception E)
                {
                    return("Application can´t send your EMail - See The Help Content EMailSender - Sending Error\n\n"+E.Message);
                        
                }
            }
            else
                return ("Empty Message body and/or empty ´To´, ´From´ fields EMailSender - Information");
                  
    
        }